A review of applications of energy analysis: Grain, fruit and vegetable drying technology

In the agricultural processing industry, drying technology plays a crucial role in ensuring product quality, extending shelf life, and reducing transportation costs. Given the rising energy prices and increasingly strict environmental regulations, enhancing the energy efficiency of drying technologies has become an urgent priority. This study systematically reviews widely used drying technologies in grain and fruit and vegetable processing, including hot air, heat pump, infrared, convection, vacuum, solar energy, fluidized bed, microwave, refraction window, and freeze drying. It also covers various combined drying techniques, such as solar heat pump, infrared hot air, and microwave vacuum drying. Detailed analyses were conducted on the specific energy consumption, specific heat consumption, and specific moisture extraction rate of different drying systems. The results demonstrate that Solar hybrid drying system offers the highest energy efficiency, followed by the hybrid drying system combining microwave and infrared drying. Solar hybrid drying technology has the shortest payback period, at just 0.33 years, followed by hot air drying at 0.43 years. These insights provide valuable recommendations for optimizing future equipment development and improving energy management and operational practices in the industry.